The present invention relates to an improved screw clamp, particularly for use in intravenous parenteral fluid feeding systems.
Intravenous sets for the introduction of parenteral solution through venipuncture typically include a piercer for insertion into a parenteral solution container, a flexible plastic tube such as polyvinylchloride for transporting the parenteral fluid from the solution container to the patient, and a needle adapter to which an intravenous needle is attached. The typical intravenous set also includes a clamp which closes the internal bore of the flexible tubing to control the flow rate of the parenteral fluid. The flow rate is determined by a fluid flow meter such as a drip chamber positioned intermediate the piercer and the needle adapter and upstream of the clamp.
In using the intravenous set, the clamp is closed, the piercer fully inserted into the solution container and the container appropriately suspended. The flow of parenteral fluid is started such as by squeezing the drip chamber until it is partially full and then the intravenous needle is attached to the needle adapter. The clamp is then opened to allow parenteral solution to displace air in the tubing, meter and needle. Subsequently, the clamp is closed and the venipuncture performed. The flow of parenteral fluid is adjusted by using the clamp and the flow rate determined using the fluid flow meter.
Several different types of clamps and other valvetype elements for use with flexible tubing are known to the art. These include screw clamps, lever clamps and cam clamps, all of which act to close the internal bore of the tubing and thereby selectively prevent the passage of fluid. Known clamps, however, are difficult to handle since they typically require the use of both hands to adjust the compression of the tubing. This is particularly disadvantageous when the clamp is used with an intravenous set requiring a multiplicity of operations as outlined above. Accordingly, it would be advantageous to have a clamp which could quickly and easily be operated using only one hand, leaving the other hand free to perform other functions which may be required such as in the operation of the fluid flow meter in the intravenous set. Many known clamps are also complicated and difficult to manufacture and accordingly relatively expensive, and so these clamps are not well suited for use with an intravenous set which is discarded after one use.
In view of the foregoing, an object of the present invention is to provide an improved screw clamp for clamping a flexible tubing which is particularly suited for use in an intravenous parenteral fluid feeding system.
A further object of the present invention is to provide a clamp which can be quickly and easily operated using only one hand and can, if desired, be easily moved longitudinally of the tubing to adjust the clamping position thereon.
Still another object of the present invention is to provide an economical clamp which can be easily fabricated and will carry out the other objects of the invention.